Text messaging has become a very popular mode of communication in many wireless communication networks. One example of text messaging is Short Message Service (SMS), which is a communication protocol allowing the exchange of short text messages (i.e., 160 characters) between mobile devices. While the term “text message” traditionally referred to text-only messages sent using SMS, it has been extended to include multimedia messages, such as images, video, sound content, etc. The multimedia messages may be sent using Multimedia Message Service (MMS) protocol. Often times, mobile users more frequently use text messaging for communication than voice calls.
Text messaging is typically implemented over the voice portion of a mobile network. One type of mobile network is based on CDMA2000 standards, and is referred to herein as a CDMA network (or ANSI-41 network). A CDMA network uses CDMA channel access to send voice, data, and signaling between mobile phones and cell sites. The general CDMA2000 standards includes CDMA2000 1X for sending text messages. For example, a sender of a new text message enters one or more intended destinations for the message in a user device (e.g., a phone), and also enters the content of the message. The user device of the sender formats the text message into the ANSI signaling message, and sends the ANSI signaling message to a message center in the network over the appropriate signaling channels. One example of a typical message center is an SMS Center (SMSC). The SMSC then attempts to deliver the SMS message to its destination(s).
The CDMA 2000 standards also define a data portion of the mobile network, which is referred to as a CDMA 1X EV-DO (Evolved Data Only or Evolved Data Optimized) or a High-Rate Packet Data (HRPD) network. An HRPD network (also referred to as a 1×EV-DO network) is a 3G high-speed CDMA-based wireless data technology that allows for data rates up to 2.4 mbps. The trend for mobile networks is to evolve towards 4G technologies. One project within the 3rd Generation Partnership Project (3GPP, 3GPP2) is the Long Term Evolution (LTE), which is a 4G (or pre-4G) technology intended to reach data rates of 100 mbps or more. The architecture defined by this project is referred to as the Evolved Packet System (EPS). The EPS architecture comprehends E-UTRAN (Evolved UTRAN) on the access side and EPC (Evolved Packet Core) on the core side.
As networks evolve to 4G networks, the HRPD networks will evolve to LTE networks. In the mean time, the CDMA 2000 standards suggest an Evolved HRPD (eHRPD) network, which is a stopgap between the EV-DO network and the LTE network. The eHRPD network allows a network operator to upgrade an existing HRPD packet core network using elements of an EPC architecture. Additionally, an eHRPD network is an evolutionary path to an LTE network while also allowing for seamless service mobility (including seamless hand-offs) between the eHRPD network and the LTE network.